The present invention relates to an air bag of a driver side air bag device installed in a central portion of a steering wheel of a vehicle, and more particularly to a driver side air bag provided with a sheet-like member within a bag body thereof for controlling the direction of the flow of gases from an inflator.
FIG. 5 is a perspective view showing an air bag for protecting a driver of an automobile (hereinafter, referred to xe2x80x9cdriver side air bagxe2x80x9d) in the deployed state, in which a bag body 14 of the air bag comprises a front panel 10 and a rear panel 12 each formed by a circular fabric and is made by sewing together the panels along the peripheries. The rear panel 12 is provided with an inflator-fitting opening 16 in the center thereof for receiving a front end of the inflator. The rear panel 12 is also provided with small holes 18 around the opening 16 through which bolts, pins, or rivets are inserted for fixing the bag body 14 to a retainer. Numeral 20 designates a vent hole for allowing gases in the bag body to escape outside when a driver plunges into the air bag.
In order to prevent the air bag from projecting forwardly during the deployment, the front panel 10 and the rear panel 12 are connected by tether belts 22 as shown in FIGS. 6-8. The tether belts 22 are sewn on the front panel 10. The tether belts 22 are also sewn on a ring-like fabric 24 disposed around the opening 16.
The bag body 14 is fixed to a retainer 30 and is covered by a module cover 32. When the air bag is deployed with gases from an inflator 54, the module cover 32 is torn and opened as shown in the drawing. The tether belts 22 are tensioned on the deployment of the air bag, thereby preventing the further advance of the front panel 10.
In Japanese Laid-open Patent No. 5-213143/1993, it is described that an inner air bag is disposed in an outer air bag and the inner air bag is in the same configuration as the outer air bag but with proportionally reduced dimensions. The inner air bag is formed in a bag shape by sewing together circular front and rear panels along the peripheries thereof in the same manner as the outer air bag. Therefore, it takes a great deal of man-hours to sew them.
Gases from the inflator are supplied into the inner air bag to inflate the inner air bag. The inner air bag is provided with a gas outlet on the rear side thereof so that the outer air bag is inflated with gases flowing out of the inner air bag through the gas outlet.
Using the tether belts 22 as shown in FIGS. 6-8 prevents the forward projection of the air bag. When the air bag is deployed, significantly large impact is applied to the tether belts 22. For that, it is necessary to quite securely sew the tether belts 22, the front panel 10, and the ring-like fabric 24. It takes a great deal of man-hours to sew them.
It is a first object of the present invention to provide a driver side air bag comprising a member, of which structure is quite simple, for controlling the direction of the flow of gases in the air bag.
It is a second object of the present invention to provide a driver side air bag in which the impact which is applied to tether belts during the deployment of the air bag is small.
A driver side air bag of the present invention comprises a bag body to be deployed in a circular shape and an inflator-fitting opening formed in a rear face of said bag body at the center of the rear face. A rectangular sheet having a central portion facing to said inflator-fitting opening and ends is fixed to said bag body around said inflator-fitting opening is disposed inside said bag body. Further, a driver side air bag of the present invention comprises a bag body to be deployed in a circular shape and an inflator-fitting opening formed in a rear face of said bag body at the center of the rear face. A cruciform sheet has a central portion facing to said inflator-fitting opening and extended portions extending in four directions from the central portion. The cruciform sheet is fixed to the bag body around the inflator-fitting opening. The cruciform sheet is disposed inside said bag body and each end of the sheet is provided with an inflator-inserting opening.
In the aforementioned driver side air bag, directions of gases from the inflator can be controlled in such a manner that the gases flow in the lateral direction of the sheet. When tether belts are disposed inside the air bag, impact applied to the tether belts during the deployment of the air bag can be reduced. The sheet employed in the present invention has a simple configuration so as to allow the easy manufacturing.